i'm working on a script in perl.
This script read a DB and generate config file for other devices.
I have a problem with "0".
From my database, i get a 0 (int) and i want this 0 become a "0" in the config file. When i get any other value (1,2,3, etc), the script generate ("1","2","3", etc). But the 0 become an empty string "".
I know, for perl:
- undef
- 0
- ""
- "0"
are false.
How can i convert a 0 to "0" ? I try qw,qq,sprintf, $x = $x || 0, and many many more solutions.
I juste want to make a explicit conversion instead of an implicite conversion.
Thank you for your help.
If you think you have zero, but the program thinks you have an empty string, you are probably dealing with a dualvar. A dualvar is a scalar that contains both a string and a number. Perl usually returns a dualvar when it needs to return false.
For example,
$ perl -we'my $x = 0; my $y = $x + 1; CORE::say "x=$x"'
x=0
$ perl -we'my $x = ""; my $y = $x + 1; CORE::say "x=$x"'
Argument "" isn't numeric in addition (+) at -e line 1.
x=
$ perl -we'my $x = !1; my $y = $x + 1; CORE::say "x=$x"'
x=
As you can see, the value returned by !1 acts as zero when used as a number, and acts as an empty string when used as a string.
To convert this dualvar into a number (leaving other numbers unchanged), you can use the following:
$x ||= 0;
